The U.S. Nuclear Regulatory Commission has regulatory jurisdiction for the medical use of radioactive materials. Title 10 of the Code of Federal Regulations contains the relevant standards for protection against radiation. The maximum occupational radiation exposure limit for radiation workers is 5000 mrem per year (total effective dose) or 50,000 mrem per year for skin or extremities. 2 Special training and individual radiation monitoring devices (film badges) are required only for those who are likely to be exposed to more than 10[percnt] of the annual exposure limits. 3
The exposure limit for nonradiation hospital personnel, such as pathology staff, including pregnant women, is 500 mrem per year, provided that the institution is authorized by the Nuclear Regulatory Commission and has procedures to maintain the dose as low as reasonably achievable. 4
Doses of 0.4 to 1.0 mCi 99mtechnetium[ndash]sulfur colloid are typically used in sentinel lymphadenectomy for melanoma and breast cancer. Mean radiation dose to the skin of a surgeon's hand during sentinel lymphadenectomy has been reported to be approximately 10 mrem for breast cancer and 2 mrem for melanoma, 14 whereas the total effective dose is estimated to be less than 0.1 mrem. 15 At these measured exposure rates, a surgeon theoretically could perform several thousand such operations each year and not exceed statutory exposure limits. 14 Mean radiation dose to pathology staff exposed to these specimens has been rarely measured but is much lower than that to the surgeon because of the shorter time spent handling the specimens. 15,18
The half-life of 99mtechnetium is 6 hours, and radiation levels decrease to background levels after 10 half-lives (60 hrs). One group reported that film badge readings of pathology staff exposed to such specimens never exceeded minimum detectable levels of 10 mrem per month. 12,17
Institutional Policy and Procedure
Each institution should develop written procedures for handling radioactive pathology specimens. These procedures should encompass specimen handling and labeling, transportation, storage, and disposal and should be designed to keep radiation exposure to laboratory and other hospital workers as low as reasonably achievable. 5 The policy should distinguish between tissue specimens obtained during sentinel lymphadenectomy, in which the amount of radiation is low, and radiation implant devices that may have significantly higher radiation levels. The institution should document that laboratory and surgery personnel handling such specimens are aware of the policy. 6
The institution should also document that all personnel handling these specimens, including couriers, are aware that the specimens contain low levels of radioactivity. Although the risk of radiation exposure is low, failure to inform workers fully that they are handling or transporting radioactive specimens may be considered a breach of the employer's responsibility.
Radiation Safety Officer
Procedures for handling radioactive tissue specimens must be developed in conjunction with the institution's radiation safety officer. The radiation safety officer has the overall responsibility for developing safety procedures, determining exposure risk to laboratory personnel, and determining whether swipe surveys or other measurements of radioactivity are needed. The radiation safety officer is also responsible for the training of surgical and pathology staff with respect to radiation safety issues.
Procedures for handling these specimens should follow standard safety guidelines established for all specimen types (that is, universal precautions). Because of the low risk of radiation exposure to pathology staff, universal precautions adequately cover most aspects of sentinel lymphadenectomy specimen handling.
The policy should describe how specimen containers are labeled. The Code of Federal Regulations states that containers of licensed radioactive material must be labeled [ldquo]Caution[mdash]Radioactive Material,[rdquo] but there are specific exceptions provided. Labeling is not required for containers holding less than 1000 [mgr]Ci 99mtechnetium or those attended by individuals who take the precautions necessary to prevent exposure in excess of the statutory limits. Labeling is also exempted if containers are accessed only by authorized individuals, provided that the contents are identified by a readily available written record. 7 Thus, if procedures are in place to avoid specimen handling by unauthorized individuals, special labeling of containers other than that for any pathology specimen is not required.
The requisition slip that accompanies the tissue must indicate the nature of the specimen (for example, sentinel lymph node after technetium injection) and include the date and time of surgery. If labels indicating radioactive material have been attached to the container, they must be removed before disposal. 8
Specimens containing radioactive materials should be promptly transported from the operating room to the laboratory in sealed, properly labeled specimen containers. The policy should specify how these specimens are transported to the laboratory and take into account the possible need for intraoperative pathology consultation. The specimen transportation policy should ensure that these specimens are not left unattended in unsecured holding areas before transport to the laboratory or frozen section room and that unsuspecting workers are not exposed for prolonged periods. Only those personnel given proper training, as determined by the radiation safety officer, should be authorized to handle radioactive specimens.
There is disagreement regarding whether these specimens should be quarantined before gross examination. Some authors have suggested holding specimens for as long as 72 hours before processing or until radioactivity decreases to background levels. 1,13,14 Others think that this recommendation is unnecessary because the level of exposure to pathology staff is not a safety concern. 11,12
Besides the exceedingly low radiation exposure to pathology staff, holding specimens for one or more days delays the final diagnosis and may increase the chance of processing errors, such as misplaced specimens or suboptimal fixation. For these reasons, holding sentinel lymph nodes before processing does not appear to be justified.
A quarantine of the primary tumor excision specimen may be considered because of the higher radioactivity levels in these specimens as compared with the sentinel lymph node. This decision, however, should be based on a determination by the radiation safety officer that measured exposure levels exceed acceptable limits.
Frozen Section Equipment
Because removable contamination is present in the cryostat immediately after frozen section analysis, one may choose to use a dedicated cryostat or clean the cryostat between uses. 14 The amount of radioactive material present in frozen section shavings, however, is limited, and most authors have not recommended special precautions. 17
Protective wear such as disposable gloves, surgical scrubs, and plastic aprons should be worn when handling these specimens. Any protective wear used when handling radioactive tissue specimens should be removed before leaving the laboratory area.
The policy should specify how these specimens are stored until disposal. Radioactive specimens should be held in a secure location to prevent unauthorized access and premature disposal. Some institutions keep tissue specimens in shielded containers until disposal, 17 but an acceptable alternative is to store these materials away from laboratory and other personnel.
Federal law allows routine methods of solid medical waste disposal for radioactive specimens after decay in storage, 9 which requires 10 half-lives. 10 Because the half-life of 99mtechnetium is 6 hours, sentinel lymphadenectomy specimens and related surgical materials can be disposed through ordinary medical waste disposal methods 60 hours after the time of surgery. If specimen containers have been specially labeled (that is, Caution[mdash]Radioactive Material), federal law requires that these labels be removed before disposal with regular medical waste. 8
Personnel monitoring devices (film badges) are not necessary for pathology staff because of the low levels of radioactivity, rapid decay, and limited time of exposure. 3
Transportation of Paraffin Blocks
It is recommended that paraffin blocks be held for 48 hours from the time of surgery before sending through the mail.
These recommendations were developed by the Surgical Pathology Committee of the College of American Pathologists, composed of Patrick L. Fitzgibbons, MD (chair), Larry Burgart, MD, David Carter, MD, Cheryl Coffin, MD, Solon Cole, MD, Megan Dishop, MD, Max Elliott, MD, David Frishberg, MD, Lloyd Gardner, MD, Kathleen Kagan-Hallet, MD, Janice Lage, MD, Virginia LiVolsi, MD, Raouf Nakhleh, MD, Mary Nielsen, MD, Frances O'Malley, MD, Henry Tazelaar, MD, Mark Weiss, MD, Bruce Wenig, MD, Reginald Wilson, MD, and endorsed by the Association of Directors of Anatomic and Surgical Pathology.
1. Cochran AJ. Surgical pathology remains pivotal in the evaluation of `sentinel' lymph nodes. Am J Surg Pathol 1999; 23[colon]1169[ndash]72.
2. Code of Federal Regulations. Occupational dose limits for adults. 10CFR20.1201. Washington, DC[colon] Government Printing Office, 1991.
3. Code of Federal Regulations. Conditions requiring individual monitoring of external and internal occupational dose. 10CFR20.1502. Washington, DC[colon] Government Printing Office, 1998.
4. Code of Federal Regulations. Dose limits for individual members of the public. 10CFR20.1301. Washington, DC[colon] Government Printing Office, 1991.
5. Code of Federal Regulations. ALARA (as low as reasonably achievable) program. 10CFR35.20. Washington, DC[colon] Government Printing Office, 1991.
6. Code of Federal Regulations. Instructions to workers. 10CFR19.12. Washington, DC[colon] Government Printing Office, 1995.
7. Code of Federal Regulations. Exemptions to labeling requirements. 10CFR20.1905. Washington, DC[colon] Government Printing Office, 1995.
8. Code of Federal Regulations. Labeling containers. 10CFR20.1904. Washington, DC[colon] Government Printing Office, 1991.
9. Code of Federal Regulations. General requirements. 10CRR20.2001. Washington, DC[colon] Government Printing Office, 1991.
10. Code of Federal Regulations. Decay-in-storage. 10CFR35.92. Washington, DC[colon] Government Printing Office, 1993.
11. Cody HS. Breast Diseases[colon] A Year Book Quarterly
12. Glass EC, Basinski JE, Krasne DL, et al. Radiation safety considerations for sentinel node techniques [lsqb]Editorial[rsqb]. Ann Surg Oncol 1999; 6[colon]10[ndash]11.
13. Messina JL, Glass F, Cruse CW, et al. Pathologic examination of the sentinel lymph node in malignant melanoma. Am J Surg Pathol 1999; 23[colon]686[ndash]90.
14. Miner TJ, Shriver CD, Flicek PR, et al. Guidelines for the safe use of radioactive materials during localization and resection of the sentinel lymph node. Ann Surg Oncol 1999; 6[colon]75[ndash]82.
15. State of California Department of Health Services. Radiation Safety Advisory 99[ndash]1, 1999.
16. Stratmann SL, McCarty TM, Kuhn JA. Radiation safety with breast sentinel node biopsy. Am J Surg 1999; 178[colon]454[ndash]7.
17. Turner RR, Giuliano AE, Hoon DSB, et al. Pathologic examination of the sentinel lymph node for breast carcinoma. World J Surg
2000. In press.
18. Veronesi U, Paganelli G, Viale G, et al. Sentinel lymph node biopsy and axillary dissection in breast cancer[colon] results in a large series. J Natl Cancer Inst 1999; 91[colon]368[ndash]73.